[hal] Initial SystemCore empty HAL (#7454)

hal/src/main/native/systemcore/HALInitializer.cpp

@@ -0,0 +1,14 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "HALInitializer.h"
+
+#include "hal/HALBase.h"
+
+namespace hal::init {
+std::atomic_bool HAL_IsInitialized{false};
+void RunInitialize() {
+  HAL_Initialize(500, 0);
+}
+}  // namespace hal::init